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Auto-upgrade free instructions to calls to the builtin free function. 

Update all analysis passes and transforms to treat free calls just like FreeInst.
Remove RaiseAllocations and all its tests since FreeInst no longer needs to be raised.

llvm-svn: 84987
This commit is contained in:
Victor Hernandez 2009-10-24 04:23:03 +00:00
parent 46ed1f8341
commit e297149e26
30 changed files with 169 additions and 269 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
llvm/docs/Passes.html
View File

@ -158,7 +158,6 @@ perl -e '$/ = undef; for (split(/\n/, <>)) { s:^ *///? ?::; print " <p>\n" if !
<tr><td><a href="#memcpyopt">-memcpyopt</a></td><td>Optimize use of memcpy and friends</td></tr>
<tr><td><a href="#mergereturn">-mergereturn</a></td><td>Unify function exit nodes</td></tr>
<tr><td><a href="#prune-eh">-prune-eh</a></td><td>Remove unused exception handling info</td></tr>
<tr><td><a href="#raiseallocs">-raiseallocs</a></td><td>Raise allocations from calls to instructions</td></tr>
<tr><td><a href="#reassociate">-reassociate</a></td><td>Reassociate expressions</td></tr>
<tr><td><a href="#reg2mem">-reg2mem</a></td><td>Demote all values to stack slots</td></tr>
<tr><td><a href="#scalarrepl">-scalarrepl</a></td><td>Scalar Replacement of Aggregates</td></tr>
@ -1502,17 +1501,6 @@ if (X &lt; 3) {</pre>
</p>
</div>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
<a name="raiseallocs">Raise allocations from calls to instructions</a>
</div>
<div class="doc_text">
<p>
Converts <tt>@malloc</tt> and <tt>@free</tt> calls to <tt>malloc</tt> and
<tt>free</tt> instructions.
</p>
</div>
<!-------------------------------------------------------------------------- -->
<div class="doc_subsection">
<a name="reassociate">Reassociate expressions</a>

2
llvm/include/llvm-c/Transforms/IPO.h
View File

@ -54,7 +54,7 @@ void LLVMAddLowerSetJmpPass(LLVMPassManagerRef PM);
/** See llvm::createPruneEHPass function. */
void LLVMAddPruneEHPass(LLVMPassManagerRef PM);
/** See llvm::createRaiseAllocationsPass function. */
// FIXME: Remove in LLVM 3.0.
void LLVMAddRaiseAllocationsPass(LLVMPassManagerRef PM);
/** See llvm::createStripDeadPrototypesPass function. */

11
llvm/include/llvm/Analysis/MallocHelper.h
View File

@ -27,8 +27,8 @@ class Value;
// malloc Call Utility Functions.
//
/// isMalloc - Returns true if the the value is either a malloc call or a
/// bitcast of the result of a malloc call
/// isMalloc - Returns true if the value is either a malloc call or a bitcast of
/// the result of a malloc call
bool isMalloc(const Value* I);
/// extractMallocCall - Returns the corresponding CallInst if the instruction
@ -80,6 +80,13 @@ const Type* getMallocAllocatedType(const CallInst* CI);
Value* getMallocArraySize(CallInst* CI, LLVMContext &Context,
const TargetData* TD);
//===----------------------------------------------------------------------===//
// free Call Utility Functions.
//
/// isFreeCall - Returns true if the the value is a call to the builtin free()
bool isFreeCall(const Value* I);
} // End llvm namespace
#endif

3
llvm/include/llvm/Instructions.h
View File

@ -956,6 +956,9 @@ public:
const Type *IntPtrTy, const Type *AllocTy,
Value *ArraySize = 0, Function* MallocF = 0,
const Twine &Name = "");
/// CreateFree - Generate the IR for a call to the builtin free function.
static void CreateFree(Value* Source, Instruction *InsertBefore);
static Instruction* CreateFree(Value* Source, BasicBlock *InsertAtEnd);
~CallInst();

1
llvm/include/llvm/LinkAllPasses.h
View File

@ -107,7 +107,6 @@ namespace {
(void) llvm::createPostDomPrinterPass();
(void) llvm::createPostDomOnlyViewerPass();
(void) llvm::createPostDomViewerPass();
(void) llvm::createRaiseAllocationsPass();
(void) llvm::createReassociatePass();
(void) llvm::createSCCPPass();
(void) llvm::createScalarReplAggregatesPass();

2
llvm/include/llvm/Support/StandardPasses.h
View File

@ -96,8 +96,6 @@ namespace llvm {
return;
}
if (UnitAtATime)
PM->add(createRaiseAllocationsPass()); // call %malloc -> malloc inst
PM->add(createCFGSimplificationPass()); // Clean up disgusting code
if (UnitAtATime) {
PM->add(createGlobalOptimizerPass()); // Optimize out global vars

7
llvm/include/llvm/Transforms/IPO.h
View File

@ -68,13 +68,6 @@ ModulePass *createConstantMergePass();
ModulePass *createGlobalOptimizerPass();
//===----------------------------------------------------------------------===//
/// createRaiseAllocationsPass - Return a new pass that transforms malloc and
/// free function calls into malloc and free instructions.
///
ModulePass *createRaiseAllocationsPass();
//===----------------------------------------------------------------------===//
/// createDeadTypeEliminationPass - Return a new pass that eliminates symbol
/// table entries for types that are never used.

4
llvm/lib/Analysis/IPA/Andersens.cpp
View File

@ -1017,6 +1017,8 @@ bool Andersens::AnalyzeUsesOfFunction(Value *V) {
}
} else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(*UI)) {
if (AnalyzeUsesOfFunction(GEP)) return true;
} else if (isa<FreeInst>(*UI) || isFreeCall(*UI)) {
return false;
} else if (CallInst *CI = dyn_cast<CallInst>(*UI)) {
// Make sure that this is just the function being called, not that it is
// passing into the function.
@ -1038,8 +1040,6 @@ bool Andersens::AnalyzeUsesOfFunction(Value *V) {
} else if (ICmpInst *ICI = dyn_cast<ICmpInst>(*UI)) {
if (!isa<ConstantPointerNull>(ICI->getOperand(1)))
return true; // Allow comparison against null.
} else if (isa<FreeInst>(*UI)) {
return false;
} else {
return true;
}

7
llvm/lib/Analysis/IPA/GlobalsModRef.cpp
View File

@ -240,6 +240,8 @@ bool GlobalsModRef::AnalyzeUsesOfPointer(Value *V,
} else if (BitCastInst *BCI = dyn_cast<BitCastInst>(*UI)) {
if (AnalyzeUsesOfPointer(BCI, Readers, Writers, OkayStoreDest))
return true;
} else if (isa<FreeInst>(*UI) || isFreeCall(*UI)) {
Writers.push_back(cast<Instruction>(*UI)->getParent()->getParent());
} else if (CallInst *CI = dyn_cast<CallInst>(*UI)) {
// Make sure that this is just the function being called, not that it is
// passing into the function.
@ -261,8 +263,6 @@ bool GlobalsModRef::AnalyzeUsesOfPointer(Value *V,
} else if (ICmpInst *ICI = dyn_cast<ICmpInst>(*UI)) {
if (!isa<ConstantPointerNull>(ICI->getOperand(1)))
return true; // Allow comparison against null.
} else if (FreeInst *F = dyn_cast<FreeInst>(*UI)) {
Writers.push_back(F->getParent()->getParent());
} else {
return true;
}
@ -439,7 +439,8 @@ void GlobalsModRef::AnalyzeCallGraph(CallGraph &CG, Module &M) {
if (cast<StoreInst>(*II).isVolatile())
// Treat volatile stores as reading memory somewhere.
FunctionEffect |= Ref;
} else if (isMalloc(&cast<Instruction>(*II)) || isa<FreeInst>(*II)) {
} else if (isMalloc(&cast<Instruction>(*II)) || isa<FreeInst>(*II) ||
isFreeCall(&cast<Instruction>(*II))) {
FunctionEffect |= ModRef;
}

26
llvm/lib/Analysis/MallocHelper.cpp
View File

@ -263,3 +263,29 @@ Value* llvm::getMallocArraySize(CallInst* CI, LLVMContext &Context,
assert(BO && "getMallocArraySize not constant but not multiplication either");
return BO->getOperand(0);
}
/// isFreeCall - Returns true if the the value is a call to the builtin free()
bool llvm::isFreeCall(const Value* I) {
const CallInst *CI = dyn_cast<CallInst>(I);
if (!CI)
return false;
const Module* M = CI->getParent()->getParent()->getParent();
Function *FreeFunc = M->getFunction("free");
if (CI->getOperand(0) != FreeFunc)
return false;
// Check free prototype.
// FIXME: workaround for PR5130, this will be obsolete when a nobuiltin
// attribute will exist.
const FunctionType *FTy = FreeFunc->getFunctionType();
if (FTy->getReturnType() != Type::getVoidTy(M->getContext()))
return false;
if (FTy->getNumParams() != 1)
return false;
if (FTy->param_begin()->get() != Type::getInt8PtrTy(M->getContext()))
return false;
return true;
}

8
llvm/lib/Analysis/MemoryDependenceAnalysis.cpp
View File

@ -118,6 +118,10 @@ getCallSiteDependencyFrom(CallSite CS, bool isReadOnlyCall,
// FreeInsts erase the entire structure
PointerSize = ~0ULL;
} else if (isFreeCall(Inst)) {
Pointer = Inst->getOperand(0);
// calls to free() erase the entire structure
PointerSize = ~0ULL;
} else if (isa<CallInst>(Inst) || isa<InvokeInst>(Inst)) {
// Debug intrinsics don't cause dependences.
if (isa<DbgInfoIntrinsic>(Inst)) continue;
@ -314,6 +318,10 @@ MemDepResult MemoryDependenceAnalysis::getDependency(Instruction *QueryInst) {
MemPtr = LI->getPointerOperand();
MemSize = AA->getTypeStoreSize(LI->getType());
}
} else if (isFreeCall(QueryInst)) {
MemPtr = QueryInst->getOperand(0);
// calls to free() erase the entire structure, not just a field.
MemSize = ~0UL;
} else if (isa<CallInst>(QueryInst) || isa<InvokeInst>(QueryInst)) {
CallSite QueryCS = CallSite::get(QueryInst);
bool isReadOnly = AA->onlyReadsMemory(QueryCS);

7
llvm/lib/AsmParser/LLParser.cpp
View File

@ -2800,7 +2800,7 @@ bool LLParser::ParseInstruction(Instruction *&Inst, BasicBlock *BB,
// Memory.
case lltok::kw_alloca: return ParseAlloc(Inst, PFS);
case lltok::kw_malloc: return ParseAlloc(Inst, PFS, BB, false);
case lltok::kw_free: return ParseFree(Inst, PFS);
case lltok::kw_free: return ParseFree(Inst, PFS, BB);
case lltok::kw_load: return ParseLoad(Inst, PFS, false);
case lltok::kw_store: return ParseStore(Inst, PFS, false);
case lltok::kw_volatile:
@ -3496,12 +3496,13 @@ bool LLParser::ParseAlloc(Instruction *&Inst, PerFunctionState &PFS,
/// ParseFree
/// ::= 'free' TypeAndValue
bool LLParser::ParseFree(Instruction *&Inst, PerFunctionState &PFS) {
bool LLParser::ParseFree(Instruction *&Inst, PerFunctionState &PFS,
BasicBlock* BB) {
Value *Val; LocTy Loc;
if (ParseTypeAndValue(Val, Loc, PFS)) return true;
if (!isa<PointerType>(Val->getType()))
return Error(Loc, "operand to free must be a pointer");
Inst = new FreeInst(Val);
Inst = CallInst::CreateFree(Val, BB);
return false;
}

2
llvm/lib/AsmParser/LLParser.h
View File

@ -280,7 +280,7 @@ namespace llvm {
bool ParseCall(Instruction *&I, PerFunctionState &PFS, bool isTail);
bool ParseAlloc(Instruction *&I, PerFunctionState &PFS,
BasicBlock *BB = 0, bool isAlloca = true);
bool ParseFree(Instruction *&I, PerFunctionState &PFS);
bool ParseFree(Instruction *&I, PerFunctionState &PFS, BasicBlock *BB);
bool ParseLoad(Instruction *&I, PerFunctionState &PFS, bool isVolatile);
bool ParseStore(Instruction *&I, PerFunctionState &PFS, bool isVolatile);
bool ParseGetResult(Instruction *&I, PerFunctionState &PFS);

3
llvm/lib/Bitcode/Reader/BitcodeReader.cpp
View File

@ -2073,7 +2073,8 @@ bool BitcodeReader::ParseFunctionBody(Function *F) {
if (getValueTypePair(Record, OpNum, NextValueNo, Op) ||
OpNum != Record.size())
return Error("Invalid FREE record");
I = new FreeInst(Op);
if (!CurBB) return Error("Invalid free instruction with no BB");
I = CallInst::CreateFree(Op, CurBB);
InstructionList.push_back(I);
break;
}

1
llvm/lib/Transforms/IPO/CMakeLists.txt
View File

@ -19,7 +19,6 @@ add_llvm_library(LLVMipo
PartialInlining.cpp
PartialSpecialization.cpp
PruneEH.cpp
RaiseAllocations.cpp
StripDeadPrototypes.cpp
StripSymbols.cpp
StructRetPromotion.cpp

5
llvm/lib/Transforms/IPO/GlobalOpt.cpp
View File

@ -1364,10 +1364,11 @@ static GlobalVariable *PerformHeapAllocSRoA(GlobalVariable *GV,
OrigBB->getParent());
BasicBlock *NextBlock = BasicBlock::Create(Context, "next",
OrigBB->getParent());
BranchInst::Create(FreeBlock, NextBlock, Cmp, NullPtrBlock);
Instruction *BI = BranchInst::Create(FreeBlock, NextBlock,
Cmp, NullPtrBlock);
// Fill in FreeBlock.
new FreeInst(GVVal, FreeBlock);
CallInst::CreateFree(GVVal, BI);
new StoreInst(Constant::getNullValue(GVVal->getType()), FieldGlobals[i],
FreeBlock);
BranchInst::Create(NextBlock, FreeBlock);

2
llvm/lib/Transforms/IPO/IPO.cpp
View File

@ -63,7 +63,7 @@ void LLVMAddPruneEHPass(LLVMPassManagerRef PM) {
}
void LLVMAddRaiseAllocationsPass(LLVMPassManagerRef PM) {
unwrap(PM)->add(createRaiseAllocationsPass());
// FIXME: Remove in LLVM 3.0.
}
void LLVMAddStripDeadPrototypesPass(LLVMPassManagerRef PM) {

173
llvm/lib/Transforms/IPO/RaiseAllocations.cpp
View File

@ -1,173 +0,0 @@
//===- RaiseAllocations.cpp - Convert @free calls to insts ------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the RaiseAllocations pass which convert free calls to free
// instructions.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "raiseallocs"
#include "llvm/Transforms/IPO.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
#include "llvm/Instructions.h"
#include "llvm/Pass.h"
#include "llvm/Support/CallSite.h"
#include "llvm/Support/Compiler.h"
#include "llvm/ADT/Statistic.h"
#include <algorithm>
using namespace llvm;
STATISTIC(NumRaised, "Number of allocations raised");
namespace {
// RaiseAllocations - Turn @free calls into the appropriate
// instruction.
//
class VISIBILITY_HIDDEN RaiseAllocations : public ModulePass {
Function *FreeFunc; // Functions in the module we are processing
// Initialized by doPassInitializationVirt
public:
static char ID; // Pass identification, replacement for typeid
RaiseAllocations()
: ModulePass(&ID), FreeFunc(0) {}
// doPassInitialization - For the raise allocations pass, this finds a
// declaration for free if it exists.
//
void doInitialization(Module &M);
// run - This method does the actual work of converting instructions over.
//
bool runOnModule(Module &M);
};
} // end anonymous namespace
char RaiseAllocations::ID = 0;
static RegisterPass<RaiseAllocations>
X("raiseallocs", "Raise allocations from calls to instructions");
// createRaiseAllocationsPass - The interface to this file...
ModulePass *llvm::createRaiseAllocationsPass() {
return new RaiseAllocations();
}
// If the module has a symbol table, they might be referring to the free
// function. If this is the case, grab the method pointers that the module is
// using.
//
// Lookup @free in the symbol table, for later use. If they don't
// exist, or are not external, we do not worry about converting calls to that
// function into the appropriate instruction.
//
void RaiseAllocations::doInitialization(Module &M) {
// Get free prototype if it exists!
FreeFunc = M.getFunction("free");
if (FreeFunc) {
const FunctionType* TyWeHave = FreeFunc->getFunctionType();
// Get the expected prototype for void free(i8*)
const FunctionType *Free1Type =
FunctionType::get(Type::getVoidTy(M.getContext()),
std::vector<const Type*>(1, PointerType::getUnqual(
Type::getInt8Ty(M.getContext()))),
false);
if (TyWeHave != Free1Type) {
// Check to see if the prototype was forgotten, giving us
// void (...) * free
// This handles the common forward declaration of: 'void free();'
const FunctionType* Free2Type =
FunctionType::get(Type::getVoidTy(M.getContext()), true);
if (TyWeHave != Free2Type) {
// One last try, check to see if we can find free as
// int (...)* free. This handles the case where NOTHING was declared.
const FunctionType* Free3Type =
FunctionType::get(Type::getInt32Ty(M.getContext()), true);
if (TyWeHave != Free3Type) {
// Give up.
FreeFunc = 0;
}
}
}
}
// Don't mess with locally defined versions of these functions...
if (FreeFunc && !FreeFunc->isDeclaration()) FreeFunc = 0;
}
// run - Transform calls into instructions...
//
bool RaiseAllocations::runOnModule(Module &M) {
// Find the free prototype...
doInitialization(M);
bool Changed = false;
// Process all free calls...
if (FreeFunc) {
std::vector<User*> Users(FreeFunc->use_begin(), FreeFunc->use_end());
std::vector<Value*> EqPointers; // Values equal to FreeFunc
while (!Users.empty()) {
User *U = Users.back();
Users.pop_back();
if (Instruction *I = dyn_cast<Instruction>(U)) {
if (isa<InvokeInst>(I))
continue;
CallSite CS = CallSite::get(I);
if (CS.getInstruction() && !CS.arg_empty() &&
(CS.getCalledFunction() == FreeFunc ||
std::find(EqPointers.begin(), EqPointers.end(),
CS.getCalledValue()) != EqPointers.end())) {
// If no prototype was provided for free, we may need to cast the
// source pointer. This should be really uncommon, but it's necessary
// just in case we are dealing with weird code like this:
// free((long)ptr);
//
Value *Source = *CS.arg_begin();
if (!isa<PointerType>(Source->getType()))
Source = new IntToPtrInst(Source,
Type::getInt8PtrTy(M.getContext()),
"FreePtrCast", I);
new FreeInst(Source, I);
// If the old instruction was an invoke, add an unconditional branch
// before the invoke, which will become the new terminator.
if (InvokeInst *II = dyn_cast<InvokeInst>(I))
BranchInst::Create(II->getNormalDest(), I);
// Delete the old call site
if (I->getType() != Type::getVoidTy(M.getContext()))
I->replaceAllUsesWith(UndefValue::get(I->getType()));
I->eraseFromParent();
Changed = true;
++NumRaised;
}
} else if (GlobalValue *GV = dyn_cast<GlobalValue>(U)) {
Users.insert(Users.end(), GV->use_begin(), GV->use_end());
EqPointers.push_back(GV);
} else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(U)) {
if (CE->isCast()) {
Users.insert(Users.end(), CE->use_begin(), CE->use_end());
EqPointers.push_back(CE);
}
}
}
}
return Changed;
}

14
llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
View File

@ -26,6 +26,7 @@
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/MallocHelper.h"
#include "llvm/Analysis/MemoryDependenceAnalysis.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Transforms/Utils/Local.h"
@ -49,7 +50,7 @@ namespace {
}
bool runOnBasicBlock(BasicBlock &BB);
bool handleFreeWithNonTrivialDependency(FreeInst *F, MemDepResult Dep);
bool handleFreeWithNonTrivialDependency(Instruction *F, MemDepResult Dep);
bool handleEndBlock(BasicBlock &BB);
bool RemoveUndeadPointers(Value* Ptr, uint64_t killPointerSize,
BasicBlock::iterator& BBI,
@ -88,7 +89,7 @@ bool DSE::runOnBasicBlock(BasicBlock &BB) {
Instruction *Inst = BBI++;
// If we find a store or a free, get its memory dependence.
if (!isa<StoreInst>(Inst) && !isa<FreeInst>(Inst))
if (!isa<StoreInst>(Inst) && !isa<FreeInst>(Inst) && !isFreeCall(Inst))
continue;
// Don't molest volatile stores or do queries that will return "clobber".
@ -103,8 +104,8 @@ bool DSE::runOnBasicBlock(BasicBlock &BB) {
if (InstDep.isNonLocal()) continue;
// Handle frees whose dependencies are non-trivial.
if (FreeInst *FI = dyn_cast<FreeInst>(Inst)) {
MadeChange |= handleFreeWithNonTrivialDependency(FI, InstDep);
if (isa<FreeInst>(Inst) || isFreeCall(Inst)) {
MadeChange |= handleFreeWithNonTrivialDependency(Inst, InstDep);
continue;
}
@ -165,7 +166,7 @@ bool DSE::runOnBasicBlock(BasicBlock &BB) {
/// handleFreeWithNonTrivialDependency - Handle frees of entire structures whose
/// dependency is a store to a field of that structure.
bool DSE::handleFreeWithNonTrivialDependency(FreeInst *F, MemDepResult Dep) {
bool DSE::handleFreeWithNonTrivialDependency(Instruction *F, MemDepResult Dep) {
AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
StoreInst *Dependency = dyn_cast_or_null<StoreInst>(Dep.getInst());
@ -175,7 +176,8 @@ bool DSE::handleFreeWithNonTrivialDependency(FreeInst *F, MemDepResult Dep) {
Value *DepPointer = Dependency->getPointerOperand()->getUnderlyingObject();
// Check for aliasing.
if (AA.alias(F->getPointerOperand(), 1, DepPointer, 1) !=
Value* FreeVal = isa<FreeInst>(F) ? F->getOperand(0) : F->getOperand(1);
if (AA.alias(FreeVal, 1, DepPointer, 1) !=
AliasAnalysis::MustAlias)
return false;

40
llvm/lib/Transforms/Scalar/InstructionCombining.cpp
View File

@ -286,6 +286,7 @@ namespace {
Instruction *visitGetElementPtrInst(GetElementPtrInst &GEP);
Instruction *visitAllocaInst(AllocaInst &AI);
Instruction *visitFreeInst(FreeInst &FI);
Instruction *visitFree(Instruction &FI);
Instruction *visitLoadInst(LoadInst &LI);
Instruction *visitStoreInst(StoreInst &SI);
Instruction *visitBranchInst(BranchInst &BI);
@ -9747,6 +9748,9 @@ Instruction *InstCombiner::SimplifyMemSet(MemSetInst *MI) {
/// the heavy lifting.
///
Instruction *InstCombiner::visitCallInst(CallInst &CI) {
if (isFreeCall(&CI))
return visitFree(CI);
// If the caller function is nounwind, mark the call as nounwind, even if the
// callee isn't.
if (CI.getParent()->getParent()->doesNotThrow() &&
@ -11337,6 +11341,42 @@ Instruction *InstCombiner::visitFreeInst(FreeInst &FI) {
return 0;
}
Instruction *InstCombiner::visitFree(Instruction &FI) {
Value *Op = FI.getOperand(1);
// free undef -> unreachable.
if (isa<UndefValue>(Op)) {
// Insert a new store to null because we cannot modify the CFG here.
new StoreInst(ConstantInt::getTrue(*Context),
UndefValue::get(Type::getInt1PtrTy(*Context)), &FI);
return EraseInstFromFunction(FI);
}
// If we have 'free null' delete the instruction. This can happen in stl code
// when lots of inlining happens.
if (isa<ConstantPointerNull>(Op))
return EraseInstFromFunction(FI);
// FIXME: Bring back free (gep X, 0,0,0,0) into free(X) transform
if (isMalloc(Op)) {
if (CallInst* CI = extractMallocCallFromBitCast(Op)) {
if (Op->hasOneUse() && CI->hasOneUse()) {
EraseInstFromFunction(FI);
EraseInstFromFunction(*CI);
return EraseInstFromFunction(*cast<Instruction>(Op));
}
} else {
// Op is a call to malloc
if (Op->hasOneUse()) {
EraseInstFromFunction(FI);
return EraseInstFromFunction(*cast<Instruction>(Op));
}
}
}
return 0;
}
/// InstCombineLoadCast - Fold 'load (cast P)' -> cast (load P)' when possible.
static Instruction *InstCombineLoadCast(InstCombiner &IC, LoadInst &LI,

3
llvm/lib/Transforms/Scalar/SCCP.cpp
View File

@ -30,6 +30,7 @@
#include "llvm/LLVMContext.h"
#include "llvm/Pass.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/MallocHelper.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Support/CallSite.h"
@ -401,6 +402,8 @@ private:
void visitLoadInst (LoadInst &I);
void visitGetElementPtrInst(GetElementPtrInst &I);
void visitCallInst (CallInst &I) {
if (isFreeCall(&I))
return;
visitCallSite(CallSite::get(&I));
}
void visitInvokeInst (InvokeInst &II) {

3
llvm/lib/Transforms/Utils/Local.cpp
View File

@ -24,6 +24,7 @@
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/DebugInfo.h"
#include "llvm/Analysis/MallocHelper.h"
#include "llvm/Analysis/ProfileInfo.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
@ -59,7 +60,7 @@ bool llvm::isSafeToLoadUnconditionally(Value *V, Instruction *ScanFrom) {
// If we see a free or a call which may write to memory (i.e. which might do
// a free) the pointer could be marked invalid.
if (isa<FreeInst>(BBI) ||
if (isa<FreeInst>(BBI) || isFreeCall(BBI) ||
(isa<CallInst>(BBI) && BBI->mayWriteToMemory() &&
!isa<DbgInfoIntrinsic>(BBI)))
return false;

6
llvm/lib/Transforms/Utils/LowerAllocations.cpp
View File

@ -102,12 +102,8 @@ bool LowerAllocations::runOnBasicBlock(BasicBlock &BB) {
// Loop over all of the instructions, looking for free instructions
for (BasicBlock::iterator I = BB.begin(), E = BB.end(); I != E; ++I) {
if (FreeInst *FI = dyn_cast<FreeInst>(I)) {
Value *PtrCast =
new BitCastInst(FI->getOperand(0),
Type::getInt8PtrTy(BB.getContext()), "", I);
// Insert a call to the free function...
CallInst::Create(FreeFunc, PtrCast, "", I)->setTailCall();
CallInst::CreateFree(FI->getOperand(0), I);
// Delete the old free instruction
I = --BBIL.erase(I);

45
llvm/lib/VMCore/Instructions.cpp
View File

@ -559,6 +559,51 @@ Instruction *CallInst::CreateMalloc(BasicBlock *InsertAtEnd,
ArraySize, MallocF, Name);
}
static Instruction* createFree(Value* Source, Instruction *InsertBefore,
BasicBlock *InsertAtEnd) {
assert(((!InsertBefore && InsertAtEnd) || (InsertBefore && !InsertAtEnd)) &&
"createFree needs either InsertBefore or InsertAtEnd");
assert(isa<PointerType>(Source->getType()) &&
"Can not free something of nonpointer type!");
BasicBlock* BB = InsertBefore ? InsertBefore->getParent() : InsertAtEnd;
Module* M = BB->getParent()->getParent();
const Type *VoidTy = Type::getVoidTy(M->getContext());
const Type *IntPtrTy = Type::getInt8PtrTy(M->getContext());
// prototype free as "void free(void*)"
Constant *FreeFunc = M->getOrInsertFunction("free", VoidTy, IntPtrTy, NULL);
CallInst* Result = NULL;
Value *PtrCast = Source;
if (InsertBefore) {
if (Source->getType() != IntPtrTy)
PtrCast = new BitCastInst(Source, IntPtrTy, "", InsertBefore);
Result = CallInst::Create(FreeFunc, PtrCast, "", InsertBefore);
} else {
if (Source->getType() != IntPtrTy)
PtrCast = new BitCastInst(Source, IntPtrTy, "", InsertAtEnd);
Result = CallInst::Create(FreeFunc, PtrCast, "");
}
Result->setTailCall();
return Result;
}
/// CreateFree - Generate the IR for a call to the builtin free function.
void CallInst::CreateFree(Value* Source, Instruction *InsertBefore) {
createFree(Source, InsertBefore, NULL);
}
/// CreateFree - Generate the IR for a call to the builtin free function.
/// Note: This function does not add the call to the basic block, that is the
/// responsibility of the caller.
Instruction* CallInst::CreateFree(Value* Source, BasicBlock *InsertAtEnd) {
Instruction* FreeCall = createFree(Source, NULL, InsertAtEnd);
assert(FreeCall && "CreateFree did not create a CallInst");
return FreeCall;
}
//===----------------------------------------------------------------------===//
// InvokeInst Implementation
//===----------------------------------------------------------------------===//

6
llvm/test/Transforms/InstCombine/malloc-free-delete.ll
View File

@ -1,11 +1,13 @@
; RUN: opt < %s -instcombine -S | grep {ret i32 0}
; RUN: opt < %s -instcombine -globaldce -S | not grep malloc
; RUN: opt < %s -instcombine -globaldce -S | FileCheck %s
; PR1201
define i32 @main(i32 %argc, i8** %argv) {
%c_19 = alloca i8* ; <i8**> [#uses=2]
%malloc_206 = malloc i8, i32 10 ; <i8*> [#uses=1]
; CHECK-NOT: malloc
store i8* %malloc_206, i8** %c_19
%tmp_207 = load i8** %c_19 ; <i8*> [#uses=1]
free i8* %tmp_207
; CHECK-NOT: free
ret i32 0
; CHECK: ret i32 0
}

10
llvm/test/Transforms/RaiseAllocations/2004-11-08-FreeUseCrash.ll
View File

@ -1,10 +0,0 @@
; RUN: opt < %s -raiseallocs -disable-output
define void @main() {
%tmp.13 = call i32 (...)* @free( i32 32 ) ; <i32> [#uses=1]
%tmp.14 = inttoptr i32 %tmp.13 to i32* ; <i32*> [#uses=0]
ret void
}
declare i32 @free(...)

17
llvm/test/Transforms/RaiseAllocations/2007-10-17-InvokeFree.ll
View File

@ -1,17 +0,0 @@
; RUN: opt < %s -raiseallocs -stats -disable-output |& \
; RUN: not grep {Number of allocations raised}
define void @foo() {
entry:
%buffer = alloca i16*
%tmp = load i16** %buffer, align 8
invoke i32(...)* @free(i16* %tmp)
to label %invcont unwind label %unwind
invcont:
br label %finally
unwind:
br label %finally
finally:
ret void
}
declare i32 @free(...)

11
llvm/test/Transforms/RaiseAllocations/FreeCastConstantExpr.ll
View File

@ -1,11 +0,0 @@
; This situation can occur due to the funcresolve pass.
;
; RUN: opt < %s -raiseallocs -S | not grep call
declare void @free(i8*)
define void @test(i32* %P) {
call void bitcast (void (i8*)* @free to void (i32*)*)( i32* %P )
ret void
}

3
llvm/test/Transforms/RaiseAllocations/dg.exp
View File

@ -1,3 +0,0 @@
load_lib llvm.exp
RunLLVMTests [lsort [glob -nocomplain $srcdir/$subdir/*.{ll,c,cpp}]]

2
llvm/utils/findoptdiff
View File

@ -70,7 +70,7 @@ dis2="$llvm2/Debug/bin/llvm-dis"
opt1="$llvm1/Debug/bin/opt"
opt2="$llvm2/Debug/bin/opt"
all_switches="-verify -lowersetjmp -raiseallocs -simplifycfg -mem2reg -globalopt -globaldce -ipconstprop -deadargelim -instcombine -simplifycfg -prune-eh -inline -simplify-libcalls -argpromotion -tailduplicate -simplifycfg -scalarrepl -instcombine -predsimplify -condprop -tailcallelim -simplifycfg -reassociate -licm -loop-unswitch -instcombine -indvars -loop-unroll -instcombine -load-vn -gcse -sccp -instcombine -condprop -dse -dce -simplifycfg -deadtypeelim -constmerge -internalize -ipsccp -globalopt -constmerge -deadargelim -inline -prune-eh -globalopt -globaldce -argpromotion -instcombine -predsimplify -scalarrepl -globalsmodref-aa -licm -load-vn -gcse -dse -instcombine -simplifycfg -verify"
all_switches="-verify -lowersetjmp -simplifycfg -mem2reg -globalopt -globaldce -ipconstprop -deadargelim -instcombine -simplifycfg -prune-eh -inline -simplify-libcalls -argpromotion -tailduplicate -simplifycfg -scalarrepl -instcombine -predsimplify -condprop -tailcallelim -simplifycfg -reassociate -licm -loop-unswitch -instcombine -indvars -loop-unroll -instcombine -load-vn -gcse -sccp -instcombine -condprop -dse -dce -simplifycfg -deadtypeelim -constmerge -internalize -ipsccp -globalopt -constmerge -deadargelim -inline -prune-eh -globalopt -globaldce -argpromotion -instcombine -predsimplify -scalarrepl -globalsmodref-aa -licm -load-vn -gcse -dse -instcombine -simplifycfg -verify"
#counter=0
function tryit {